Showerhead tilt mechanism

ABSTRACT

A showerhead tilt adjustment mechanism is provided which supports a showerhead module in a top plate of a semiconductor substrate processing apparatus, the showerhead tilt adjustment mechanism including a differential screw which provides coarse and fine adjustments to adjust gap/tilt/planarization of a faceplate of the showerhead module with respect to an upper surface of a substrate pedestal module adjacent the faceplate in the semiconductor substrate processing apparatus.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation patent application of U.S. patentapplication Ser. No. 15/658,911, filed Jul. 25, 2017, the entire contentof which is incorporated herein by reference.

FIELD OF INVENTION

This invention pertains to semiconductor substrate processingapparatuses used for processing semiconductor substrates, and may findparticular use in performing chemical vapor depositions of thin films.

BACKGROUND

Semiconductor substrate processing apparatuses are used to processsemiconductor substrates by techniques including, physical vapordeposition (PVD), chemical vapor deposition (CVD), plasma enhancedchemical vapor deposition (PECVD), atomic layer deposition (ALD), plasmaenhanced atomic layer deposition (PEALD), pulsed deposition layer (PDL),molecular layer deposition (MLD), plasma enhanced pulsed depositionlayer (PEPDL) processing, etching, and resist removal. One type ofsemiconductor substrate processing apparatus used to processsemiconductor substrates includes a reaction chamber containing ashowerhead module and a substrate pedestal module which supports thesemiconductor substrate in the reaction chamber. The showerhead moduledelivers process gas into the reactor chamber so that the semiconductorsubstrate may be processed. In such chambers installation and removal ofthe showerhead module can be time consuming, and further, non-uniformfilm deposition (i.e. azimuthal variation) during substrate processingcan occur if a lower surface of the showerhead module is not parallel toan upper surface of the substrate pedestal module.

SUMMARY

Disclosed herein is a semiconductor substrate processing apparatus forprocessing semiconductor substrates comprising (a) a chemical isolationchamber in which individual semiconductor substrates are processed, thechemical isolation chamber including a top plate forming an upper wallof the chemical isolation chamber, (b) a process gas source in fluidcommunication with the chemical isolation chamber for supplying at leastone process gas into the chemical isolation chamber, (c) a showerheadmodule which delivers the process gas from the process gas source to aprocessing zone of the processing apparatus wherein the individualsemiconductor substrates are processed, the showerhead module includinga base attached to a lower end of a stem wherein a faceplate having gaspassages therethrough forms a lower surface of the base and the stemextends through a vertically extending bore in the top plate, (d) asubstrate pedestal module configured to support the semiconductorsubstrate in the processing zone below the faceplate during processingof the substrate, (e) a bellows assembly supporting the showerheadmodule, the bellows assembly including a collar, a bellows and aleveling plate, the collar having a central opening aligned with thebore in the top plate, the bellows surrounding the central opening inthe collar and having a lower end attached to an upper surface of thecollar and an upper end attached to a lower surface of the levelingplate, the leveling plate having a central opening aligned with the borein the top plate, and (f) at least one showerhead tilt adjustmentmechanism operable to adjust tilting of the faceplate of the showerheadmodule with respect to an upper surface of the substrate pedestal moduleadjacent the faceplate, wherein the showerhead tilt adjustment mechanismcomprises a lock screw, a hollow screw, a lock plate, and a lock nut,the hollow screw having a first threaded section on an outer surfacethereof and a second threaded section on the outer surface, the firstthreaded section having a thread pitch which is different than a threadpitch of the second threaded section, the first threaded section engagedwith an internally threaded bore of the leveling plate, the secondthreaded section engaged with an internal thread of the locking nut, thelock screw having a lower external threaded section engaged with athreaded bore in the collar and an upper screw head engaging a shoulderof an upper socket in the hollow screw, and the lock plate movable froma first position at which the lock nut rotates with the hollow screw toa second position at which the lock nut cannot rotate, the showerheadtilt adjustment mechanism providing coarse adjustment when the lockplate is in the first position and fine adjustment when the lock plateis in the second position.

The at least one showerhead tilt adjustment mechanism preferablycomprises three showerhead tilt adjustment mechanisms spaced outwardlyof the bellows at locations 120° apart. The lock plate can be movable ina radial direction between the first and second positions and/or theleveling plate can include an upwardly extending tubular section whereinan inner surface of the tubular section includes the threaded bore. Thelock plate can include a handle at an outer end thereof extendingoutwardly of the collar, a wide slot at an inner end thereof which canengage the lock nut, and a narrow slot extending outward from the wideslot, and a lock plate screw extending through the narrow slot andthreaded into the collar, the lock plate screw having a screw head whichcan be tightened against the lock plate to prevent movement of the lockplate. In a preferred embodiment, the showerhead tilt adjustmentmechanism can provide a coarse gap adjustment of about 0.02 to about0.04 inch per full rotation of the hollow screw when the lock plate isin the first position and a fine gap adjustment of about 0.002 to about0.004 inch per full rotation of the hollow screw when the lock plate isin the second position.

In an embodiment, a method of controlling in-plane distortion (IPD) dueto showerhead tilt in a semiconductor substrate processing apparatuscomprises (a) measuring IPD changes across a wafer processed in aprocessing chamber of the semiconductor substrate processing apparatus,(b) adjusting tilt of a showerhead of the semiconductor substrateprocessing apparatus using three showerhead tilt adjustment mechanismsconfigured to provide coarse and fine IPD adjustments wherein each ofthe showerhead tilt adjustment mechanisms comprises a lock screw, ahollow screw, a lock plate and a lock nut arranged to vary a gap betweena movable part attached to the showerhead and a fixed part in theprocessing chamber, (c) wherein the hollow screw has a first threadedsection on an outer surface thereof and a second threaded section on theouter surface, the first threaded section having a thread pitch which isdifferent than a thread pitch of the second threaded section, the firstthreaded section engaged with an internally threaded bore of the movablepart, and the second threaded section engaged with an internal thread ofthe locking nut, (d) the lock screw has a lower end threaded into a borein the fixed part and an upper screw head engaging a shoulder of anupper socket in the hollow screw; and (e) the lock plate is movable froma first position at which the lock nut rotates with the hollow screw toa second position at which the lock nut cannot rotate, the showerheadtilt adjustment mechanism providing coarse adjustment when the lockplate is in the first position and fine adjustment when the lock plateis in the second position. In making a coarse adjustment, the lock plateof one of the showerhead tilt adjustment mechanisms can be placed in thefirst position and the hollow screw can be rotated to a first radialposition. In making a fine adjustment, the lock plate can be moved tothe second position and the hollow screw can be rotated to a secondradial position at which the IPD is reduced. The upper socket of thehollow screw can include a slot extending through a wall of the socketand the method can further comprise placing an indicator cap having anupper alignment mark onto the hollow screw such that a projection on theindicator cap fits within the slot, recording a pre-adjustment angle ofalignment mark, removing the indicator cap and making the IPDadjustment, placing the indicator cap on the hollow screw and recordinga post-adjustment angle of the alignment mark. By using first and secondthreaded sections having the same orientation, each of the showerheadtilt adjustment mechanisms can provide a coarse gap adjustment of about0.02 to about 0.04 inch per full rotation of the hollow screw when thelock plate is in the first position and a fine gap adjustment of about0.002 to about 0.004 inch per full rotation of the hollow screw when thelock plate is in the second position.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 illustrates a schematic diagram showing an overview of a chemicaldeposition apparatus in accordance with embodiments disclosed herein.

FIG. 2 illustrates a block diagram depicting various apparatuscomponents arranged for implementing embodiments disclosed hereinwherein plasma can be utilized to enhance deposition and/or surfacereactions between reacting species during the generation of thin films.

FIG. 3A illustrates a cross-section and FIG. 3B illustrates a top viewof a showerhead module arranged in accordance with embodiments disclosedherein.

FIGS. 4A-D illustrate gap tuning arrangements wherein FIGS. 4A-B showhow coarse tuning is carried out with the lock plate not engaged with alock nut and FIGS. 4C-D show how fine tuning is carried out with thelock plate engaged with the lock nut in accordance with embodimentsdisclosed herein.

FIG. 5 illustrates how an indicator cap fits on the hollow adjustmentscrew in accordance with an embodiment disclosed herein.

FIG. 6 illustrates an indicator cap which mounts on a hollow adjustmentscrew for indicating an angle of rotation after a gap adjustment.

DETAILED DESCRIPTION

In the following detailed description, numerous specific embodiments areset forth in order to provide a thorough understanding of the apparatusand methods disclosed herein. However, as will be apparent to thoseskilled in the art, the present embodiments may be practiced withoutthese specific details or by using alternate elements or processes. Inother instances, well-known processes, procedures, and/or componentshave not been described in detail so as not to unnecessarily obscureaspects of embodiments disclosed herein. As used herein in connectionwith numerical values the term “about” refers to ±10%.

As indicated, present embodiments provide semiconductor substrateprocessing apparatuses such as deposition apparatuses (or in analternate embodiment an etching apparatus) and associated methods forconducting a chemical vapor deposition such as a plasma enhancedchemical vapor deposition. The apparatus and methods are particularlyapplicable for use in conjunction with semiconductor fabrication baseddielectric deposition processes or metal deposition processes whichrequire separation of self-limiting deposition steps in a multi-stepdeposition process (e.g., atomic layer deposition (ALD), plasma enhancedatomic layer deposition (PEALD), plasma enhanced chemical vapordeposition (PECVD), pulsed deposition layer (PDL), molecular layerdeposition (MLD), or plasma enhanced pulsed deposition layer (PEPDL)processing), however they are not so limited. Exemplary embodiments ofmethods of processing a semiconductor substrate can be found incommonly-assigned U.S. Published Patent Application Nos. 2013/0230987,2013/0005140, 2013/0319329, and U.S. Pat. Nos. 8,580,697, 8,431,033, and8,557,712, which are hereby incorporated by reference in their entirety.

The aforementioned processes can suffer from some drawbacks associatedwith non-uniform process gas delivery to an upper surface of a wafer orsemiconductor substrate receiving deposited films from process gas suchas a process gas precursor or reactant. For example, a non-uniformprecursor distribution on the upper surface of the semiconductorsubstrate can form if a lower surface of a showerhead module whichdelivers process gas to the semiconductor substrate is not parallel toan upper surface of a substrate pedestal module which supports thesemiconductor substrate. Several properties of film on wafer areimpacted by the gap/leveling between showerhead and pedestal, i.e. IPD,NU %, Stress, etc. The sensitivity between these properties and thegap/leveling are different for different process. And sometimes, thenormal resolution is not workable. To address this problem, an improvedleveling process is described herein wherein extra fine resolution of agap adjustment can be provided in a film deposition apparatus.

There are generally two main types of CVD showerhead modules: thechandelier type and the flush mount type. The chandelier showerheadmodules have a stem attached to a top plate of the reaction chamber onone end and a faceplate on the other end, resembling a chandelier. Apart of the stem may protrude above the top plate to enable connectionof gas lines and connection to a radio frequency (“RF”) power circuit.Flush mount showerhead modules are integrated into the top of a chamberand do not have a stem. Although the examples shown herein are of achandelier type showerhead, the showerhead module is not limited to thattype of showerhead.

Showerhead module leveling (planarization) is typically performed aftera wet clean procedure that involves cooling and venting a reactionchamber (chemical isolation chamber) of the apparatus one or multipletimes. The cooling and venting may be required to access the interior ofthe chamber to adjust the spacing between the showerhead and thesubstrate pedestal module as well as the planarization of a lowersurface of the showerhead with respect to an upper surface of thepedestal module. A conventional technique involves placing metallic foilballs in the chamber to measure the gap between the showerhead moduleand the substrate pedestal module and then adjusting a number ofstandoffs, usually three or more, between a backing plate of theshowerhead module and the top plate of the reaction chamber based on themeasurements. The standoffs can only be adjusted by opening the topplate after venting and cooling the chamber. Multiple measuring andadjusting cycles may be performed before the showerhead module isconsidered level. Because the showerhead cannot be leveled throughexternal manipulation, the process can be very time-consuming, up toabout 20 hours.

In an embodiment, a gap adjustment is performed with screws havingdifferential threads. In this application, a screw and two nuts areused. The screw has two threads with a different but close pitch. Eachnut has one pitch that matches the screw. With two pairs of threads, thefinal pitch is the difference/sum of the two pitches of the two pairs ofthreads. When the two threads are in the same orientation, they canprovide fine resolution. On the other hand, when the two threads are inopposite orientation, they can provide extra course resolution. Byfixing both nuts, abnormal resolution can be obtained, and by fixingonly one nut and leaving the other one free to rotate, normal resolutionis available. Thus, using the differential threads, the showerhead towafer/pedestal gap and other gaps can be adjusted with muchfiner/coarser resolution compared with the normal gap tuning method. Andwith this method, the gap can also be adjusted with the normalresolution. In this way, the gap can be tuned more precisely or faster.Thus, the showerhead to wafer/pedestal gap can be tuned more precisely,which has a large impact on IPD/NU %/etc. of film on wafers.

In accordance with an embodiment, differential threads are used toadjust the showerhead to wafer/pedestal gap. In this way, extrafine/coarse resolution can be provided. In the showerhead module, anextra nut can be added without changing the mounting plate and therebyprovide a more retrofitable/cost saving tilt adjustment arrangement. Asan example, when the two threads on the screw are in the sameorientation, extra fine resolution is available, and when they are inthe opposite orientations, extra coarse resolution is available. Inanother arrangement, final resolution can be modified by changing theresolution of the two threads. Due to space constraints in working onthe tool, a tiny wrench can be used to handle the extra nut and thusavoid the need for a specially designed wrench/tool. The tiny wrench canbe fixed with an available screw in the existing assembly and avoid theneed to manually handle the wrench during tuning. If desired, the wrenchcan be movable (wrench lock the extra nut or free the extra nut), so thetuning can be changed between abnormal resolution and normal resolution.As a visual aid during tilt adjustment, a mark on the wrench can be usedto indicate of its position, i.e., locking or free position. Also, a capwith compass mark can be used to mate with the screw head in a singleorientation. This cap is removable and before and after each tuning, amark can be made on the cap relative to a certain orientation. Then, theangle between the two marks before and after the tuning can be measuredto determine a turned angle. In this way, no auto gapping system (“AGS”)wafer measurement is required for this application which can save agreat amount of time. A discussion of AGS wafer measurements can befound in commonly-assigned U.S. Published Patent Application No.2015/0225854, the disclosure of which is hereby incorporated byreference.

Disclosed herein is a showerhead module coupled to a showerhead tiltadjustment mechanism, which is designed to be leveled from outside ofthe reaction chamber, between process steps on the same wafer. Inprocesses where two or more different film materials are depositedsequentially, dynamically adjusting showerhead tilt corrects forazimuthal variation without breaking vacuum. The showerhead tiltadjustment mechanism includes the differential screw tuning arrangementdescribed above.

also described herein is a method of controlling in-plane distortion(IPD) due to showerhead tilt in a semiconductor substrate processingapparatus. The method includes measuring IPD changes across a waferprocessed in a processing chamber of the semiconductor substrateprocessing apparatus and adjusting tilt of a showerhead of thesemiconductor substrate processing apparatus using three showerhead tiltadjustment mechanisms having the differential screw tuning arrangementdescribed above which provide coarse and fine IPD adjustments.

FIG. 1 is a schematic diagram showing an overview of a semiconductorsubstrate processing apparatus 201 for chemical vapor deposition inaccordance with embodiments disclosed herein. A semiconductor substrate13 such as a wafer sits on top of a movable pedestal module 223 that canbe raised or lowered relative to a showerhead module 211, which may alsobe moved vertically. Reactant material gases are introduced into aprocessing zone 318 of the chamber via gas line 203 wherein the processgas flow is controlled by a mass flow controller 229. Note that theapparatus may be modified to have one or more gas lines, depending onthe number of reactant gases used. The chamber is evacuated throughvacuum lines 235 that are connected to a vacuum source 209. The vacuumsource may be a vacuum pump.

Embodiments disclosed herein can be implemented in a plasma enhancedchemical deposition apparatus (i.e. plasma-enhanced chemical vapordeposition (PECVD) apparatus, plasma-enhanced atomic layer deposition(PEALD) apparatus, or plasma-enhanced pulsed deposition layer (PEPDL)apparatus). FIG. 2 provides a simple block diagram depicting variousapparatus components arranged for implementing embodiments disclosedherein wherein plasma is utilized to enhance deposition. As shown, aprocessing zone 318 serves to contain the plasma generated by acapacitively coupled plasma system including a showerhead module 211working in conjunction with a substrate pedestal module 223, wherein thesubstrate pedestal module 223 is heated. RF source(s), such as at leastone high-frequency (HF) RF generator 204, connected to a matchingnetwork 206, and an optional low-frequency (LF) RF generator 202 areconnected to the showerhead module 211. In an alternative embodiment,the HF generator 204 can be connected to the substrate pedestal module223. The power and frequency supplied by matching network 206 issufficient to generate a plasma from the process gas/vapor. In anembodiment both the HF generator and the LF generator are used, and inan alternate embodiment, just the HF generator is used. In a typicalprocess, the HF generator is operated at frequencies of about 2-100 MHz;in a preferred embodiment at 13.56 MHz or 27 MHz. The LF generator isoperated at about 50 kHz to 2 MHz; in a preferred embodiment at about350 to 600 kHz. The process parameters may be scaled based on thechamber volume, substrate size, and other factors. Similarly, the flowrates of process gas may depend on the free volume of the vacuum chamber(reaction chamber) or processing zone.

Within the chamber, the substrate pedestal module 223 supports asubstrate 13 on which materials such as thin films may be deposited. Thesubstrate pedestal module 223 can include a fork or lift pins to holdand transfer the substrate during and between the deposition and/orplasma treatment reactions. In an embodiment, the substrate 13 may beconfigured to rest on a surface of the substrate pedestal module 223,however in alternate embodiments the substrate pedestal module 223 mayinclude an electrostatic chuck, a mechanical chuck, or a vacuum chuckfor holding the substrate 13 on the surface of the substrate pedestalmodule 223. The substrate pedestal module 223 can be coupled with aheater block 220 for heating substrate 13 to a desired temperature.Substrate 13 is maintained at a temperature of about 25° C. to 500° C.or greater depending on the material to be deposited.

In certain embodiments, a system controller 228 is employed to controlprocess conditions during deposition, post deposition treatments, and/orother process operations. The controller 228 will typically include oneor more memory devices and one or more processors. The processor mayinclude a CPU or computer, analog and/or digital input/outputconnections, stepper motor controller boards, etc.

In certain embodiments, the controller 228 controls all of theactivities of the apparatus. The system controller 228 executes systemcontrol software including sets of instructions for controlling thetiming of the processing operations, frequency and power of operationsof the LF generator 202 and the HF generator 204, flow rates andtemperatures of precursors and inert gases and their relative mixing,temperature of the heater block 220 and showerhead module 211, pressureof the chamber, tilt of the showerhead, and other parameters of aparticular process. Other computer programs stored on memory devicesassociated with the controller may be employed in some embodiments.

Typically there will be a user interface associated with controller 228.The user interface may include a display screen, graphical softwaredisplays of the apparatus and/or process conditions, and user inputdevices such as pointing devices, keyboards, touch screens, microphones,etc.

A non-transitory computer machine-readable medium can comprise programinstructions for control of the apparatus. The computer program code forcontrolling the processing operations can be written in any conventionalcomputer readable programming language: for example, assembly language,C, C++, Pascal, Fortran or others. Compiled object code or script isexecuted by the processor to perform the tasks identified in theprogram.

The controller parameters relate to process conditions such as, forexample, timing of the processing steps, flow rates and temperatures ofprecursors and inert gases, temperature of the wafer, pressure of thechamber, tilt of the showerhead, and other parameters of a particularprocess. These parameters are provided to the user in the form of arecipe, and may be entered utilizing the user interface.

Signals for monitoring the process may be provided by analog and/ordigital input connections of the system controller. The signals forcontrolling the process are output on the analog and digital outputconnections of the apparatus.

The system software may be designed or configured in many differentways. For example, various chamber component subroutines or controlobjects may be written to control operation of the chamber componentsnecessary to carry out deposition processes. Examples of programs orsections of programs for this purpose include substrate timing of theprocessing steps code, flow rates and temperatures of precursors andinert gases code, and a code for pressure of the chamber.

The showerhead module 211 is preferably temperature controlled and thepedestal is preferably RF powered. An exemplary embodiment of atemperature controlled RF powered showerhead module can be found incommonly-assigned U.S. Published Patent Application No. 2013/0316094which is hereby incorporated by reference in its entirety.

According to embodiments disclosed herein, the showerhead modulepreferably includes a showerhead tilt adjustment mechanism for manuallyadjusting tilt, angle, gap and planarization of the showerhead module.As illustrated in FIGS. 3A and 3B, a showerhead module 211 preferablyincludes a stem 305, a base 315 which includes a backing plate 317 and afaceplate 316 as well as the showerhead tilt adjustment mechanism 400for adjusting the planarization of the showerhead module 211. Theplanarization of the showerhead module 211 can also be coarsely adjustedby tightening or loosening three adjustment screws 405 located 120°apart. Adjustment screws 405 comprise a coarse thread and a fine threadthat can be used to manually adjust the showerhead module 211 in tiltand in axial position. The adjustment screws 405 mate with lock nuts andthreaded bores in a leveling plate as explained in more detail below.

In one embodiment, planarization of the faceplate 316 of the showerheadmodule 211 can be adjusted using three tilt adjustment mechanisms aspart of a showerhead adjustment mechanism to manually provide threedegrees of freedom: an axial translation and two directions of tilt.With reference to FIGS. 3A and 3B, the showerhead module 211 issupported by a bellows assembly 500 which includes a collar 502, bellows504 and leveling plate 506. A cooling plate 508 can be attached to theleveling plate 506.

As illustrated in FIG. 3A, the showerhead module 211 is preferablysupported in a top plate 330 of the chemical isolation chamber (i.e.reaction chamber). The top plate 330 preferably supports the collar 502in a stepped bore. A horizontal upper surface of the top plate 330preferably has openings, such as threaded openings, whereincorresponding openings, for receiving fasteners 512, in the collar 502include at least three fasteners 512 which attach the collar 502 to thetop plate 330. The collar 502 supports the remainder of showerhead tiltadjustment mechanism 400 in the top plate 330. The showerhead tiltadjustment mechanism 400 is electrically grounded by the top plate 330.

An O-ring 514 forms an airtight seal (i.e. a hermetic seal) between theleveling plate 506 and the cooling plate 508 supported above the collar502 by three adjustment screws 405 wherein the three adjustment screws405 are also operable to coarsely adjust the planarization of thecooling plate 508 with respect to the collar 502. As explained in moredetail below, an upper end of each adjustment screw 405 is threaded intoa threaded bore of the leveling plate 506 and a lower end of eachrespective adjustment screw 405 is threaded into a lock nut 516 which isfree to rotate with the adjustment screw 405 when not engaged with lockplate 518 or the lock nut 516 can be locked by engagement with the lockplate 518 so as not to rotate when the adjustment screw 405 is rotated.The showerhead stem 305 extends through a central opening in the collar502, the bellows 504, and the leveling plate 506 and an upper end of thestem 305 is attached to the leveling plate 506 so that the faceplate 316can be tilted to a desired angle by rotation of the adjustment screws405.

The bellows 504 preferably forms an airtight expandable and flexiblevacuum seal between the collar 502 and the leveling plate 506 whereinthe stem 305 extends through the airtight expandable vacuum seal suchthat the planarization of the showerhead module 211 can be adjustedwithout breaking the airtight expandable vacuum seal. The bellows 504 ispreferably welded at an upper end to the leveling plate 506 and at alower end to the collar 502.

The showerhead tilt adjustment mechanism 400 may be attached to the topplate 330 of a chemical isolation chamber via three or more fasteners512. The showerhead tilt adjustment mechanism preferably includes threedifferential screw assemblies wherein each differential screw assemblyprovides one degree of motion. Three differential screw assemblies wouldgive three degrees of motion: two tilts and axial position.

FIGS. 4A-4D show further details of the showerhead tilt adjustmentmechanism and how the showerhead tilt mechanism can provide coarse andfine gap adjustments. The adjustment screw 405 includes a firstexternally threaded section 405 a engaged with an internally threadedsection 506 a in an upwardly extending tubular projection 506 b on theleveling plate 506 and a second externally threaded section 405 bengaged with internal threads of the lock screw 516. The first threadedsection 405 a and the second threaded section 405 b preferably havedifferent thread pitches oriented in the same direction. The upper endof the adjustment screw 405 includes a socket 405 c which can engage atool such as a hexagonal screw driver (not shown) and a slot 405 d in anupper portion of the socket 405 c is adapted to receive a projection ofan indicator cap. A fastener 520 such as a bolt is located inside theadjustment screw 405 with a lower end 520 a threaded into a threadedhole in the collar 502 and an enlarged head 520 b at the upper endreceived inside the socket 405 c. the head 520 b fills a lower portionof the socket 405 c so that a tool such as a hexagonal screw driver canengage the remainder of the socket 405 c to rotate the adjustment screw405 during a gap/tilt adjustment.

The lock plate 518 includes a handle 518 a at one end, a wide slot 518 bat the opposite end, and a narrow slot 518 c extending from the wideslot 518 b. The shaft of fastener 512 extends through the narrow slot518 c and allows the lock plate 518 to slide radially inwardly to engagethe lock nut 516. As shown in FIGS. 4A-4B, when the lock plate 518 isnot engaged with the lock nut 516, the lock nut 516 rotates with theadjustment screw 405 to provide a coarse gap adjustment. As shown inFIGS. 4C-4D, when the lock plate 518 is engaged with the lock nut 516,the lock nut 516 is prevented from rotating with the adjustment screw405 to provide a fine gap adjustment. The lock plate 518 includes areference mark 518 d which provides a visual indication of when the lockplate 518 is not engaged with the lock nut 516 (reference mark 518 d isoutside the outer periphery of leveling plate 506 as shown in FIGS.4A-4B) and when the lock plate 518 is engaged with the lock nut 516(reference mark 518 d is inside the outer periphery of the levelingplate 506 as shown in FIGS. 4C-4D).

FIG. 5 shows details of an indicator cap 522 fitted in the socket 405 cof the adjustment screw 405. The indicator cap 522 includes a projection522 a which fits in the slot 405 d of the adjustment screw 405. Inmaking a gap/tilt adjustment, the indicator cap 522 can be placed on theadjustment screw 405 and its angular position can be recorded. Then, theindicator cap is removed and a gap/tilt adjustment is performed byrotating the adjustment screw 405 with the lock nut 516 not engaged withthe lock plate 518 or with the lock nut 516 engaged with the lock plate518. When the gap/tilt adjustment is completed, the indicator cap isplaced on the adjustment screw 405 and its angular position is recorded.

As shown in FIG. 6, the indicator cap can include a pointer 522 bextending upwardly from a circular dial 522 c having indicatorcircumferentially spaced marks 522 d which provide a visual indicationof the angular position of the pointer before and after a gap/tiltadjustment.

The adjustment screw 405 may also be used for coarse and fine adjustmentof the showerhead module 211 position. Depending on the choice of threadpitches, coarse adjustments in the range of about 0.02 to about 0.04inch and fine adjustments in the range of about 0.002 to 0.004 inch perfull rotation of the adjustment screw 405 can be achieved. For example,the coarse adjustment can be 0.03125 inch per full rotation of theadjustment screw and the fine adjustment can be 0.0035 inch per fullrotation of the adjustment screw.

While the semiconductor substrate processing apparatus including thebaffle arrangement has been described in detail with reference tospecific embodiments thereof, it will be apparent to those skilled inthe art that various changes and modifications can be made, andequivalents employed, without departing from the scope of the appendedclaims.

What is claimed is:
 1. A semiconductor substrate processing apparatusfor processing semiconductor substrates comprising: a chemical isolationchamber in which individual semiconductor substrates are processed, thechemical isolation chamber including a top plate forming an upper wallof the chemical isolation chamber; a process gas source in fluidcommunication with the chemical isolation chamber for supplying at leastone process gas into the chemical isolation chamber; a showerhead modulewhich delivers the process gas from the process gas source to aprocessing zone of the processing apparatus wherein the individualsemiconductor substrates are processed, the showerhead module includinga base attached to a lower end of a stem wherein a faceplate having gaspassages therethrough forms a lower surface of the base and the stemextends through a vertically extending bore in the top plate; asubstrate pedestal module configured to support the semiconductorsubstrate in the processing zone below the faceplate during processingof the substrate; a bellows assembly supporting the showerhead module,the bellows assembly including a collar, a bellows and a leveling plate,the collar having a central opening aligned with the bore in the topplate, the bellows surrounding the central opening in the collar andhaving a lower end attached to an upper surface of the collar and anupper end attached to a lower surface of the leveling plate, theleveling plate having a central opening aligned with the bore in the topplate; at least one showerhead tilt adjustment mechanism operable toadjust tilting of the faceplate of the showerhead module with respect toan upper surface of the substrate pedestal module adjacent thefaceplate, wherein the showerhead tilt adjustment mechanism comprises ahollow screw, a lock plate, and a lock nut, the hollow screw having afirst threaded section and a second threaded section, the first threadedsection having a thread pitch which is different than a thread pitch ofthe second threaded section, the first threaded section engaged with theleveling plate, the second threaded section engaged with the lock nut,and the lock plate movable from a first position at which the lock nutrotates with the hollow screw to a second position at which the lock nutcannot rotate, the showerhead tilt adjustment mechanism providing coarseadjustment when the lock plate is in the first position and fineadjustment when the lock plate is in the second position.
 2. Thesemiconductor substrate processing apparatus of claim 1, wherein the atleast one showerhead tilt adjustment mechanism comprises threeshowerhead tilt adjustment mechanisms spaced outwardly of the bellows atlocations 120° apart.
 3. The semiconductor substrate processingapparatus of claim 1, wherein the lock plate is movable in a radialdirection between the first and second positions.
 4. The semiconductorsubstrate processing apparatus of claim 1, wherein the leveling plateincludes a threaded section engaging the hollow screw.
 5. Thesemiconductor substrate processing apparatus of claim 1, wherein thelock plate includes a handle at an outer end thereof extending outwardlyof the collar, a wide slot at an inner end thereof which can engage thelock nut, and a narrow slot extending outward from the wide slot, and alock plate screw extending through the narrow slot and threaded into thecollar, the lock plate screw having a screw head which can be tightenedagainst the lock plate to prevent movement of the lock plate.
 6. Thesemiconductor substrate processing apparatus of claim 1, wherein theshowerhead tilt adjustment mechanism can provide a coarse gap adjustmentof about 0.02 to about 0.04 inch per full rotation of the hollow screwwhen the lock plate is in the first position and a fine gap adjustmentof about 0.002 to about 0.004 inch per full rotation of the hollow screwwhen the lock plate is in the second position.
 7. A showerhead tiltadjustment mechanism configured to provide coarse and fine gapadjustments of a showerhead module supported in a top plate of asemiconductor substrate processing apparatus by a bellows assembly,wherein the showerhead tilt adjustment mechanism comprises: a hollowscrew, a lock plate, and a lock nut; the hollow screw having a firstthreaded section and a second threaded section, the first threadedsection having a thread pitch which is different than a thread pitch ofthe second threaded section, the first threaded section configured toengage with a leveling plate of the bellows assembly, the secondthreaded section engaged with the lock nut; the lock plate movable froma first position at which the lock nut rotates with the hollow screw toa second position at which the lock nut cannot rotate, the showerheadtilt adjustment mechanism providing coarse adjustment when the lockplate is in the first position and fine adjustment when the lock plateis in the second position.
 8. The showerhead tilt adjustment mechanismof claim 7, wherein the first and second threaded sections on the hollowscrew have the same orientation.
 9. The showerhead tilt adjustmentmechanism of claim 7, wherein the lock plate includes a handle at anouter end thereof, a wide slot at an inner end thereof which can engagethe lock nut, and a narrow slot extending outward from the wide slot,the narrow slot configured to receive a lock plate screw threaded intothe collar, the lock plate screw having a screw head which can betightened against the lock plate to prevent movement of the lock plate.10. The showerhead tilt adjustment mechanism of claim 7, wherein theshowerhead tilt adjustment mechanism can provide a coarse gap adjustmentof about 0.02 to about 0.04 inch per full rotation of the hollow screwwhen the lock plate is in the first position and a fine gap adjustmentof about 0.002 to about 0.004 inch per full rotation of the hollow screwwhen the lock plate is in the second position.
 11. A showerhead modulewhich delivers process gas from a process gas source to a processingzone of a semiconductor substrate processing apparatus whereinindividual semiconductor substrates are processed, the showerhead modulecomprising: a base attached to a lower end of a stem wherein a faceplatehaving gas passages therethrough forms a lower surface of the base andthe stem is configured to extend through a vertically extending bore ina top plate of the processing apparatus; a bellows assembly supportingthe showerhead module, the bellows assembly including a collar, abellows and a leveling plate, the collar having a central openingaligned with the bore in the top plate, the bellows surrounding thecentral opening in the collar and having a lower end attached to anupper surface of the collar and an upper end attached to a lower surfaceof the leveling plate, the leveling plate having a central openingaligned with the bore in the top plate; at least one showerhead tiltadjustment mechanism operable to adjust tilting of the faceplate of theshowerhead module, wherein the showerhead tilt adjustment mechanismcomprises a hollow screw, a lock plate, and a lock nut, the hollow screwhaving a first threaded section and a second threaded section, the firstthreaded section having a thread pitch which is different than a threadpitch of the second threaded section, the first threaded section engagedwith the leveling plate, the second threaded section engaged with thelock nut, and the lock plate movable from a first position at which thelock nut rotates with the hollow screw to a second position at which thelock nut cannot rotate, the showerhead tilt adjustment mechanismproviding coarse adjustment when the lock plate is in the first positionand fine adjustment when the lock plate is in the second position. 12.The showerhead module of claim 11, wherein the at least one showerheadtilt adjustment mechanism comprises three showerhead tilt adjustmentmechanisms spaced outwardly of the bellows at locations 120° apart. 13.The showerhead module of claim 11, wherein the lock plate is movable ina radial direction between the first and second positions.
 14. Theshowerhead module of claim 11, wherein the leveling plate includes athreaded section which engages the hollowscrew.
 15. The showerheadmodule of claim 11, wherein the lock plate includes a handle at an outerend thereof extending outwardly of the collar, a wide slot at an innerend thereof which can engage the lock nut, and a narrow slot extendingoutward from the wide slot, and a lock plate screw extending through thenarrow slot and threaded into the collar, the lock plate screw having ascrew head which can be tightened against the lock plate to preventmovement of the lock plate.
 16. The showerhead module of claim 15,wherein the showerhead tilt adjustment mechanism can provide a coarsegap adjustment of about 0.02 to about 0.04 inch per full rotation of thehollow screw when the lock plate is in the first position and a fine gapadjustment of about 0.002 to about 0.004 inch per full rotation of thehollow screw when the lock plate is in the second position.
 17. A methodof controlling deposition film properties due to showerhead tilt in asemiconductor substrate processing apparatus, the method comprising:measuring deposition film properties of a wafer processed in aprocessing chamber of the semiconductor substrate processing apparatus;adjusting tilt of a showerhead of the semiconductor substrate processingapparatus using three showerhead tilt adjustment mechanisms configuredto provide coarse and fine adjustments wherein each of the showerheadtilt adjustment mechanisms comprises a hollow screw, a lock plate and alock nut arranged to vary a gap between a movable part attached to theshowerhead and a fixed part in the processing chamber; wherein thehollow screw has a first threaded section and a second threaded section,the first threaded section having a thread pitch which is different thana thread pitch of the second threaded section, the first threadedsection engaged with the movable part, and the second threaded sectionengaged with the lock nut; and the lock plate is movable from a firstposition at which the lock nut rotates with the hollow screw to a secondposition at which the lock nut cannot rotate, the showerhead tiltadjustment mechanism providing coarse adjustment when the lock plate isin the first position and fine adjustment when the lock plate is in thesecond position.
 18. The method of claim 17, comprising making a coarseadjustment by positioning the lock plate of one of the showerhead tiltadjustment mechanisms in the first position and rotating the hollowscrew to a first radial position, and making a fine adjustment by movingthe lock plate to the second position and rotating the hollow screw to asecond radial position.
 19. The method of claim 18, wherein a slotextends through a wall of a socket in the hollow screw, the methodfurther comprising placing an indicator cap having an upper alignmentmark onto the hollow screw such that a projection on the indicator capfits within the slot, recording a pre-adjustment angle of alignmentmark, removing the indicator cap and making the deposition film propertyadjustment, placing the indicator cap on the hollow screw and recordinga post-adjustment angle of the alignment mark.
 20. The method of claim17, wherein the first and second threaded sections have the sameorientation and each of the showerhead tilt adjustment mechanisms canprovide a coarse gap adjustment of about 0.02 to about 0.04 inch perfull rotation of the hollow screw when the lock plate is in the firstposition and a fine gap adjustment of about 0.002 to about 0.004 inchper full rotation of the hollow screw when the lock plate is in thesecond position.